Electrical distribution system



Nov. 3, 1936 w, H. FRANK Er A1. 2,059,987

ELECTRICAL DISTRIBUTION SYSTEM Filed MaICh 25, 1935 3 Sheets-Sheet l lud v www, n T N EN# O B ...u 1MM A 7 2 Y. n m e g M ,m O, .r fwd A 2 n .Mw m s u 3 E wad m a m I- mmw w. 0.1 I Kmw NI Mmm Frm Hwd n www RF m ,l\

Nov. 3, 1936.

Patented Nov. 3, 1936 UNITED STATES ELECTRICAL DISTRIBUTION SYSTEM William H. Frank and Joseph W. Harper, Detroit, Mich.

Application March 25, 1935, Serial No. 12,756

8 Claims.

This application relates to electrical distribution systems. It more` particularly relates to novel interchangeable current take-off devices used in connection with bus ducts.

The device here shown is in the nature of a fused switch to which branch circuit conductors may be connected, and which may be manipulated conveniently, safely, and repeatedly, to conwith respect to the bus bars. The device here shown generally comprises an open bottom boxlike body adapted to be removably associated with the bus duct in a dust-proof manner and stationary when so associated and having contact fingers for engaging the bus bars. The contact lingers are supported on the sides of the box or body and have integral stationary contact clips adapted to be connected through other stationary contact clips and through fuses, also supported on the sides of the body, to the branch circuit conductors, and for interconnecting the contact clips of the contact iingers to the second mentioned contact clips so as to close the circuits from the bus bars to the conductors there is provided a head or cover hingedly connected tothe body and provided with a slide block carrying U-shaped bridging contacts which may be moved to bridge the sets of stationary contact clips of the stationary body and close the circuits through them. 'I'he slide block carrying the bridging contacts is movably mountedI on the hinged head so as to be capable of assuming two positions; in one position the bridging contacts will bridge the stationary contact clips when the head is swung u towards the body to form a cover therefor, and in another position the bridging contacts will not bridge the stationary contact clips when the head is swung into covering position. Means are provided for properly indexing and latching the slide o block in the desired position on the head; means are also provided whereby the position of the bridging contacts with respect to the stationary contact clips will be revealed externally of the device even when the cover is closed; and means 5 are also provided for latching the head or cover in closing position on the'body.

Details and. features of the device here shown constitute important objects of the inventions of this application, and these details will best be w understood upon reference to the appended drawings. In' these drawings, l g l Fig. 1 shows a swinging head slide contact form of current take-off device, in top plan view and in position on the bus duct; c 5 Fig. 2 shows the same in side view;

nect or disconnect the branch circuit conductors Fig. 3 shows the same in left end view;

Fig. 4 shows the device pe se in perspective View with the swinging head open and with the movable bridging .contacts in circuit closing position;

Fig. 5 is an elevational section view as if on 5 the broken line 5-5 of Fig. 1 with the swinging head closed and with the movable bridging contacts in circuit closing position;

Fig. 6 is a fragmentary view similar to that of Fig. 5 but showing the movable bridging contacts 10 in circuit open position;

Figs. 7 and 8 are right angularly related views of a duplex contact member formed at one end with contact fingers for engagement with the bus bars of the duct and formed at the other end with 15 contact clips adapted to be engaged by a prong of the movable bridging contact of the swinging head;

Fig. 9 is a section as if on the line 9-9 of Fig. 2;

Figs. l0 and 11 show a contact member per se 20 provided with an arc choking shroud;

Fig. 12 is a section as if on line I2I2 of Fig. 10;

Fig. 13 shows a modified manner of associating a contact clip and a conducting strap.

A bus duct system comprises duct run and branch circuit take-'off devices. Since the bus duct run of this case is by now well known, the bus duct run of this case will not now be shown, except in such fragments as are necessary to illustrate features of the branch circuit take-off device here shown in detail.

'I'he system of this case comprises bus duct runs equippedwith branch circuit take-off devices of various sorts, and` one of these devices will now be described in detail, with reference to its cooperation with the duct shown here.

The device here shown comprises two major parts, namely, a body A and a head B, and the latter is hingedly connected to the body by means of hinges C whereby it may be swung towards or 40 from the body and close or open thelatter as desired.

'I'he body comprises a sheet metal box II) having an open bottom and top and having downwardly extending sides I I which it on opposite sides I5 of the duct and are bolted thereto by the bolts I6 which pass through the duct flanges I1 and connect the duct halves. The holes for these bolts I6 are so positioned with respect to uniformly spaced access holes or crescent shaped 60 openings of the duct, through which contact ngers of the body may pass, that proper alignment of these contact iingers with the duct access holes for engaging the bus bars I8 is assured by tightening of the bolts ls.

' straps 32 and fuse clips 33, and to the straps 32 Inside the body box i, at the end near the hinges C, is a vitreous insulation connection block 28 having partitions 2| which divide it into cells in which are disposed fuse clips 23 and connection straps 24 provided with cable terminal lugs 25 of the solderless type hereinafter to be described in detail.

Connected to these lugs are the bared terminals of cables 25 which passes out of the sheet metal box I8 through a selected one of the knock-outs 21 in draw-outs oi' opposite sides of the box I8. At the opposite end o! the box I8 is a vitreous insulation contact block 28 having partitions 38 dividing it into cells corresponding in number to the cells of the connection block 28. 'I'he cells-of the contact block receive connection are secured the bights of U-shaped contact clips 34, these comprising one of the two sets of stationary contact clips of the body A. The bights of theyclips 34 are secured to the straps 32 by screws, as in Fig. 6, or in the full floating mannerl shown in Fig. 13, wherein ends of the clips are received in notches of the straps 32. The blocks 28 and 38.are supported from the sides of the box, inasmuch as the bottom and top oi.' the box are open, and all of the parts are designed with this thought in mind. 'I'his is particularly true of the blocks which are grooved in such a manner that the grooves extend in the direction of the screws which secure the blocks to the sides of the box.

In slots on the ends of the connection block 28 are duplex contact members |34 formed of straps whose ends are shaped to provide contact ngers |35 and contact clips |350, the straps being resiliently and full floatingly supported and reinforced at two points between their ends by means of transverse pins |38 provided with pressure reinforcing springs |31, substantially as shown in Figs. 9 and 13. The contact straps are enclosedy within insulating protecting tubes 34a carried by a supporting strap |38 through which the pins |38 lpassin a manner to support the duplex contact members |34, and the supporting strap |38 is insulatedly mounted on the contact block 28 through the medium of mounting screws |38. l

'I'he contact ngers |35 engage the bus bars I8, as shown in Fig. 3, and the clips |35a provide the second set of stationary contact clips for the body A; for this purposethe clips |35al are aligned with the rst set ot stationary contacts provided by the contact clips 34. 4

Ihe contact block 28 is formed to shield the contact clips 34 and |35a completely except for deep narrow slots |48 in line with the alined entrances to these contact clips, and accidental engagement with the contact clips is thus' prohibited. Between the clips 34 and |38a there is provided a barrier or shield |4| and the same cooperate with shoulders of the blocks to separate and isolate 'the clips 34 from the clips |38a.'

Fuses 35 are disposed in the box and these bridge the fuse clips 23 in the connection vblock and-the fuse clips 33 in the contact blockl to complete the circuit from the clips 34 to the cables 28.

bottom of the'box 8 to forma gasket for the latter and complete the dust-proof closure ef Iected by the latter when it is xedly positioned I@ and a felt 'Ihe blocks 28 are provided with integral bosses 43 projecting through holes in the end of the box I8, and these bosses have ne holes 44 therethrough which ailord accessfrom outside the'.

device to the connection straps 24 for the reception of i'use test leads which will engage the load side straps 24; fuse testing may thu's be accomplished readily and easily from the lload side of the device.

As has been stated above, the head B is hingedly mounted on the body A, the fastenings being in the nature of hinges C, and when the head is swung into position on the body it closes the open top box I8; a spring latch referenced generally 58 and manually manipulable is provided for latching the head B in closing position on the body, and a pivotal bail 5| is provided to facilitate swinging of the head from and towards the body. l

Slidably mounted on the head near the end thereof that matches the end of the box I8 containing the contact block 28 is a slide block 54 of vitreous insulation.

The latter is provided with pins and spacers 55 which ride in guide slots -formed in a plate 58 secured to the head B, and a plate 51 into which thread the pins 55 rides in the space between the plate 58 and a draw-out portion 58 of the y y plate B, whereby the slide block 54 will be guided in its movement along the head. The plate 58 is also provided with holes for the reception oi a spring actuated manipulable indexing pin 58 resiliently carried by the slide block 54 to index the latter in either of the two positions shown in Figs. 5vand 6, and it is here observed that the cooperation o! the pins 55 and the guide slots of plate 88 is such that a considerable amount of play is Provided for the slide block 54 in its movement and in its on and o!! positions, whereby the U-shaped bridging contacts 88 mounted on the block, and having prongs 8| 82 may have a full floating movement with respect to the head B and the body clips 34 and |35a which are also mounted to "oat.

The draw-out portion 51 of the head B is provided with a transparent window 83 through which on and oi! markings on the plate 51 carried by the slidev block pins 55 may be viewed, these markings indicating which of the two indexed positions is occupied by the slide block and its contacts 88. v

When the slide block is in the position of Fig. 5, prongs 8l engage the clips I35a, and prongs 82 engage the clips 34 when the head B is swung towards thebody. With the parts in this position, the circuits from the bus bars to the branch circuit conductors will be completed.

However, if the slide block 54 is moved to the' gaged by the prongs 8| and the circuits from the L bus bars to the branch circuit cables will not be closed. Under *such circumstances,` though prongs 8| will make with clips 34, clips |35a` and prongs 82 will be electrically free of one another and consequently the circuits will remain open. 'lyhe engagement of prongs 8| andclips 34 will help hold the' cover closed. ythough closing 'no electrical circuit.

'Ihe terminal lugs 28 may be in the formof cup-shaped hollow metal blocks having integral shanks .18 riveted over through holes of the lstraps and may have aligned apertures u through which may be passed the bared terminal ends 'I2 of the-,cables 26, these being clamped in place by the set screws 13 threaded into the cups of the lugs 25.

It wm be observed that while the insulation tubes 34a operate to quench arcs that may be 4formed when the clips |35 of the contact members |34 are separated from the bus bars |8 oi the duct, nevertheless these tubes might not operate as eiiiciently as desired. Consequently, an arc choking shroud of the type shown in Figs. -12 may be employed. This shroud comprises trough-like` closures 8l) resiliently mounted at 8| on the contacts |34 and having end closing portions 82 which cooperate to form complete closures around the contacts |34 as shown' in Figs. 10-12l Now having described the device here shown, reference should be had to the appended claims for a determination of the monopoly sought to be covered herein.

We claim:

l. An electrical distribution system comprising elongated bus duct having an entrance through which a prong may be inserted for direct contact with a bar, and a branch circuit take off device comprising a switch having a body'and a movable cover, 2 the body having a pair of aligned contactslongitudinally spaced along the duct, one of the-m being connected to the bus bar by means of a bus bar engaging prong of the body entering the duct through the entrance, and the other being connected to a branch conductor, the cover having a bridging contact adapted to bridge the bodyj contacts when in one position and when the cover is closed, and movbar by means of a bus bar engaging prong of able longitudinally alongthe duct from that position so as not to bridge the body contacts even whenv the cover ,is closed, the cover contact being slidably mounted on the cover` so as to be reciprocable from one to the other of its two positions inthe line of the contacts without being removed from the cover.

2. An electrical distributionsystem comprising elongated' bus duct having an entrance through.

which a prong may be inserted for direct contact with a bar, and a branch circuit take oif device comprising a Vswitch having a movable cover, the body having a pair of contacts, one of thenbeing connected to the bus which a prong may be inserted for direct contact with a bus bar, and a branch circuit take oi device comprising a body inthe nature of an open bottom and open top box provided with sides engaging and fixed to .opposite sides of the duct and having a pair of alined contacts supported on a block mounted on and connecting the sides ofthe box and to one of which a branch circuit conductor may be connected, the other of the body contacts being connetced to a bus bar through a prong entering the duct entrance avbody and i and engaging abus bar, the device also compris- .ing a cover mounted on the box and closing its open top and having a bridging contact adapted to bridge the body contacts when in one position and when the cover is closed to connect the engaged bus bar and the branch circuit conductor, and movable from that position so as not to bridge the body contacts even when the cover is closed, the cover contact being movably mounted on the cover so as to be movable without being removed from the cover, the open bottorn of the box being closed by the'duct.

4. An' electrical distribution system comprising elongated bus duct having an entrance through which a prong may be inserted for direct contact With a bus bar, and a branch circuit take off device comprising a body in the nature of an open bottom and open top box provided with sides engaging and fixed to opposite sides of the duct and having a pair of alined contacts longitudinally spaced along the duct and supported on a block mounted on and connecting the sides of thev box and to one of which a branch circuit conductor may be connected through a fuse in the body, the other of the body contacts being connected to a bus bar through a prong enteringthe duct entrance and engaging a bus bar, the device also comprising a cover mounted on the box and closing its open top and having a bridging contact adapted to bridge the body contacts when in one position and when the cover .is closed to connect the engaged bus bar and the branch circuit conductor, and movable from that position so as not to bridge the body vcontacts even when the cover is closed, the cover contact being slidably mounted on the cover and along the longitudinal run of the duct so as to be reciprocable along the duct without being removed l from the cover, the open bottom of the box being closed'by the duct.

5. An electrical distribution system comprising elongated bus duct having an entrance through which a prong may be inserted for direct contact with a bus bar, and a branch circuit take oif device comprising a body in the nature of an open bottom and open top box provided with sides engaging and xed to opposite sides of the duct and/having a pair of alined contacts supported on a block mounted on and connecting-...the sides of the box and to one of which a branch circuit conductor may be connected, 4the other of the bo'dy contacts being connected to a bus bar through a prong entering the duct lentrance and engaging a bus bar, the device also comprising a cover mounted on the box and closing its open top and having a bridging contact adapted to bridge the body contacts when in one position and when the cover is closed to connect the engaged bus bar and the branch circuit'conductor, and movable from that position so as not to bridge the body contacts even when the cover is closed, the cover contact being movaoly mounted on he'cover so as to be movable withbut being removed from the cover, the open bottom of the box being closed by the duct and a fuse incircuit with the bus b ar, the aligned contacts, the prong, and the bridging contact and. supported on a block mounte and connecting the sides of the box.

6. An electrical distribution system comprising elongated bus duct having an entrance through which a prong may be inserted for direct Contact with a bus bar, and a branch circuit take off device comprising a bodf.7 in the nature of an open bottom and open top box provided with side engaging and fixed to opposite sides of the duct and having a pair of aiined contacts supported on a block mounted on and connecting the sides of the box and to one of which a branch circuit conductor may be connected, the other of the body contacts being connected to a bus barv through a prong entering the duct entrance and engaging a bus bar, the device also comprising a cover mounted on the box and closing its open top and having a bridging contact adapted to bridge the body contacts when in one position and when the cover is closed to connect the engaged bus bar and the branch circuit conductor, and movable from that position so as not to bridge the body contacts even when the cover is closed, the cover contact being movablyv mounted on the cover so as to be movable without being removed from the cover, the open bottom of the box being closed by the duct, and a fuse in circuit with the bus bar, the aligned contacts, the prong, and the bridging contact and supported on a block mounted on and connecting the sides of the box, the fuse extending'longitudinally of the duct run.

'1. An electrical distribution system comprising elongated bus duct having an entrance through which a prong may be inserted for direct contact with a bus bar, and a branch cir- Acuit take oi! device comprising a body fixed to the duct and having a pair of contacts and to one of which a branch circuit conductor may be connected, the other of the body contacts being connected to a bus bar through a prong entering the duct entrance and engaging a bus bar, the device also comprising a cover having a bridging contact movably mounted thereon and adapted to bridge the body contacts when the cover is closed and the contact is in one of its two positions to connect the engaged bus bar and the branch circuit conductor, the contact being movable, independently of the cover, to be out of bridging relation to the body contacts.

8. An electrical distribution system comprising elongated bus duct having an entrance through which a prong may be inserted for direct contact with a busbar, and a branch circuit take of! device comprising a body in the nature o! an open bottom and open top=box provided with sides engaging andiixed to opposite sides of the duct and having a pair of alignedcontacts longitudinally spaced along the duct and supported on a block mounted on and connecting the sides of the box and to one of which a branch circuit conductor may be connected through a fuse in the body, the other of the body contacts being connected to a bus bar through a prong entering the duct entrance and engaging a bus bar. the device also comprising a cover mounted on the box and closing its open top and having a bridging contact adapted to bridge the body contacts when in one position and when the cover is alom to connect the engaged bus bar and the branch circuit conductor, and movable from that position so as not to bridge the body contacts even when the cover is closed the cover contact being siidably mounted on the cover and along the longitudinal run of the duct so as to be reciproble along the duct without being removed from the cover, the open bottom of the box being closed by the duct. and a fuse in circuit with the bus bar, the aligned contacts, the prong, and the bridging contact and supported on a block molmted on and connecting the sides of the box, the fuse extending longitudinally of the duct run.

- WILLIAM H. FRANK. JOSEPH W. HARPER. 

